Interpretive Summary: Ascochyta blight is a serious fungal disease of chickpea. The initial inoculum for disease development often originates from sexually produced spores (ascospores) of the pathogen, Didymella rabiei, which has survived in post-harvest chickpea debris over the winter. Ascospores are released in the spring. Laboratory studies have indicated that application of the common fungus Aureobasidium pullulans (AuP) to chickpea debris can suppress reproduction of D. rabiei. The present study confirms that analogous application of AuP to over-wintering chickpea debris can suppress disease development in either the greenhouse or the field. Manipulation of the fungal flora colonizing chickpea debris may represent another tool for disease management in chickpea.

Technical Abstract:
In 2004-2005, early winter application of suspensions of Aureobasidium pullulans (AuP) conidia to post-harvest chickpea debris resulted in significantly fewer spring-time Ascochyta blight lesions on chickpea test plants relative to controls. Survival of plants adjacent to treated debris was higher than for plants adjacent to non-treated debris. When similarly treated and over-wintered debris was transported to the greenhouse for use against test plants in 2006-2007, the plants exposed to debris treated with AuP had significantly fewer Ascochyta blight lesions than plants exposed to untreated controls. Trapping of ascospores released from over-wintered debris revealed a high relative frequency of ascospores of Davidiella sp. (anamorph, Cladosporium sp.), followed by ascospores of Didymella rabiei (anamorph, Ascochyta rabiei, the agent of Ascochyta blight), and a much lower frequency of Pleospora sp. (anamorph, Stemphylium sp.).